Vacuum failure stop motion device

ABSTRACT

A VACUUM FAILURE STOP MOTION DEVICE PARTICULARLY ADAPTED FOR USE WITH A VACUUM TAKE-DOWN SYSTEM ASSOCIATED WITH CIRCULAR KNITTING MACHINES, THE DEVICE HAVING A CHAMBER, THE BORE OF WHICH IS SUBSTANTIALLY PERPENDICULAR TO THE AXIS OF THE EVACUATING TUBE OF THE VACUUM SYSTEM. THE CHAMBER CONTAINS A MOVEABLE PISTON WHICH IN TURN IS CONNECTED TO THE ACTUATING FINGER OF A SWITCHING DEVICE SO THAT A CHANGE IN THE VACUUM MAGNITUDE WITHIN THE EVACUATING TUBE IS SENSED BY THE PISTON WHICH MOVES WITHIN THE CHAMBER AND DISPLACES THE FINGER TO ACTUATE THE SWITCH AND THUS TERMINATE THE OPERATION OF THE MACHINE.

Feb. 23, 1971 KNOX 3,564,874

VACUUM FAILURE STOP MOTION DEVICE Filed Feb. 27, 1969 L, 2 INVENTOREdward E. Knox ATTORNEY United States Patent f US. Cl. 66149 7 ClaimsABSTRACT OF THE DISCLOSURE A vacuum failure stop motion deviceparticularly adapted for use with a vacuum take-down system associatedwith circular knitting machines, the device having a chamber, the boreof which is substantially perpendicular to the axis of the evacuatingtube of the vacuum system. The chamber contains a moveable piston whichin turn is connected to the actuating finger of a switching device sothat a change in the vacuum magnitude within the evacuating tube issensed by the piston which moves within the chamber and displaces thefinger to actuate the switch and thus terminate the operation of themachine.

Background, brief summary and objectives of the invention A number ofmachines used in the production of fabric and garments are sensitive tomalfunctions to the extent that an interruption in the machineoperation, a defect in the partially or finally completed product or aninaccurate or improper adjustment or setting will damage the machine,the product or both. For example, a knitting machine for producingladies hosiery and the hosiery produced thereon are especially sensitiveto sequential product withdrawal because a stocking which is not drawnaway from the knitting instrumentalities properly can cause substantialdamage to the machine if it continues to operate and will, itself,obviously become damaged. The present invention relates to an apparatuswhich can be attached to conventional machines such as those used in theproduction of apparel for controlling machine Operation and especiallyto a device which can be attached to a conventional circular knittingmachine that will deactivate the machine and prevent machine or garmentdamage when a malfunction occurs.

It is conventional practice to include on a circular knitting machine adevice or means for applying tension downwardly on the hosiery beingknit to ensure consistent and reliable stitch formation. A number ofmechanical tensioning devices are often utilized, and in many cases, aflow of air is used to tension the fabric during the knitting operation.The vacuum or suction type tensioning device is quite effective inpulling the stocking away from the knitting needles to achieve thedesired result.

Unfortunately, these vacuum devices, which are in quite widespread use,occasionally fail, either because of a radical fluctuation in pressuresupply or because one or more of the article-carrying tubes on one ormore of the machines becomes blocked when a knit stocking is not ejectedproperly. In such instances, the operation of the machine is impairedbecause the next stocking is started without the previous stocking beingremoved. When the previous stocking is not cleared from the needles in asatisfactory manner, commencement of the knitting operation for the nextstocking can lead to a breakage of knitting needles requiringconsiderable downtime and maintenance to correct as well as a loss ofthe stocking involved.

To monitor the conventional suction system often used for the stockingtakedown operation and to prevent damage to machines and the stockingsunder construction in ice the event the vacuum system is activated forone reason or another, the present invention operates to shut down theknitting machine in the event the vacuum fails or varies greatly for anyreason. The device is generally comprised of a small chambercommunicating with the evacuating tube of the vacuum system leading fromthe knitting machine in which is carried a displaceable batfie. A pistonrod connects with the bafile and extends outwardly from the chamber. Airmovement to the chamher from the evacuation tube is through a series ofapertures provided in the wall of the main tube. An activating device ispositioned adjacent the chamber, and a conventional microswitch or othersuitable activating and deactivating mechanism is preferred. The switchcontains a moveable finger which functions as an operating or triggeringdevice and is connected to the free end of the piston rod. So long as avacuum is present in the evacuating tube of the suction system, thebaffle and connecting rod will be drawn toward the main tube and holdthe switching device through the movable finger in the open (or closed)position. Upon failure of the vacuum, the piston will be urged away fromthe main tube by the spring of the moveable finger of the switch. Thusthe switch will close (or open) the circuit will become deenergized andthis deenergization through the proper circuit arrangement will in turndeactivate the circular knitting machine.

From the foregoing discussion, it is clear that a primary object of thepresent invention is to provide a vacuum failure stop motion device ofthe type described which will effectively terminate the operation of atextile machine upon failure of the vacuum system when articles ofapparel are not sequentially and properly removed as produced.

Another object of the present invention is to provide a vacuum failurestop motion device of the type described which is particularly adaptableto circular knitting ma. chines for knitting tubular articles utilizingvacuum take down systems that draw the knitted articles away from theknitting instrumentalities.

Yet another object of the present invention is to provide a device ofthe type described which is extremely simple in construction,inexpensive to manufacture and reliable in operation.

A further object of the present invention is to provide a evice of thetype described which can be installed on conventional circular knittingmachines embodying a vacuum take down system without any substantialmodification being made on the machine or the vacuum system.

These and other objects and advantages of the invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings wherein like characters of reference designatelike parts throughout the several views.

Figure description FIG. 1 is a perspective, fragmentary view of acircular knitting machine illustrating one application of the presentinvention as applied to the suction take down system of a circularknitting machine.

FIG. 2 is a perspective, fragmentary and enlarged view of the vacuumfailure stop motion device comprising the present invention and itsassociation with the evacuating tube of a vacuum system such as usedwith circular knitting machines.

Detailed description of the invention The present invention is a sensingdevice which can be applied to a conventional circular knitting machineutilizing a vacuum take-down system that is adapted to stop the machinewhen the vacuum system malfunctions for one reason or another or themagnitude of the vacuum within that system fluctuates beyond establishedlimits. Referring to the drawings and particularly to FIG. 1, aconventional circular knitting machine shown generally as has a frame12. and a fabric receiving tube 14 which is connected to a sealedtubular member 16 serving as the commencement of the evacuating tubegenerally indicated as 18. During the machine operation as the stockingis being knit, a vacuum is established from a remote source (not shown)within the evacuating tube system 18 to draw down the stocking as it islengthened within the tube 14 by the kniting operation. The stockingextends downwardly through the initial tubular member 16 because of thevacuum existing therein as a result of suction from the remote source.The entire tubular system is sealed so that maximum suction within thesystem is experienced.

Normally the stocking, upon completion of the knitting operation, willbe released from the needles and will be taken up through the tubularsystem 18 into the main vacuum trunk line 20. The trunk line extends toa receptacle collecting the knit garments from one or more knittingmachines. The machines are arranged to deposit the knit stockings intothe trunk line by a connecting section 22. So long as the vacuum systemis operating properly, each independently knit stocking is sequentiallydischarged from the knitting instrumentalities of the machine andintroduced into the main vacuum trunk line 20 for subsequent collectionat a remote location by a suitable receptacle.

In the event the vacuum system fails or decreases in magnitude to theextent that the stocking being knit is no longer consistently drawndownwardly from the knitting needles, the knitting operation is impairedand the lack of tension on the stocking being knit can eventually leadto needle damage, stocking destruction and other machine impairment.

The present invention, while adaptable to any suitable machine whereinknitted articles are sequentially manufactured and discharged from thecomponents of the machine, is particularly suitable for use withcircular knitting machines for manufacturing hosiery having vacuumtake-down systems such as that illustrated in FIG. 1. The stop motiondevice shown generally as 24 is comprised of a chamber 26 thelongitudinal axis of which is substantially perpendicular to the axis ofthe evacuating tube section 28 to which the chamber is affixed.Communication from the interior of the chamber 26 to the tube section 28is through a plurality of apertures 30 drilled in the wall of section 28in any suitable or desired arrangement. The rearward portion 32 of thechamber 26 is bonded or otherwise affixed to one face 33 of an angularmember 34 which is either integrally or articulately formed in themanner shown in FIG. 2. A suitable switching mechanism shown generallyas 36 is then afiixed to one surface of member 34 in a suitable mannerso that a moveable switch-operating finger 38 extends upwardly to theaxis of chamber 26. An electrical microswitch such as that made byHoneywell and designated type BZ RW performs very satisfactorily in thisenvironment though obviously any number of commercially availablemicroswitches having conventional operating characteristics would beequally effective.

A baffle 40 which forms a piston within chamber 26 is positioned to sealgenerally the chamber as shown. A piston rod 42 connects with the bafiie'40 and extends rearwardly through an aperture 44 in face 33 of member34 and provides an attaching point for linkage 46 that is secured to themoveable finger 38 of the switch 36. The switch control circuitrepresented by conductors 48 and 50 provides the knitting machine motorcontrol.

So long as the vacuum system is operating in a normal manner, suction ispresent in the tubes 20, 22 and 24 and particularly, for illustrativepurposes, in tube section 28 of FIG. 2, A, vacuum in tube section 28draws the bafiie 40 toward the section because of the apertures 39present in the segment wall, and this holds the finger 38 of the switch36 in a position that keeps the machine control circuit in an energizedor operating state. In the event the vacuum system fails and no vacuumis present in tube section 28, the spring of the finger 38 will urge thepiston rod 42 and baffle 40 away from the tube section 28. Thus in thisinstance, the switch will be actuated and the stop motion circuit formedby conductors 48 and 50 will close or open as the case may be andterminate the operation of the knitting machine.

The device constituting the present invention can obviously be installedon each singularly driven knitting machine. When a plurality of machinesare driven from a remotely located motor through a common shaft, thecontrol circuit of each machine may be designated to disengage a clutchmechanism that drives each machine. It is also practicable and desirableto provide some of the stop motion devices on the vacuum trunk line 20communicating with a line of machines so that a failure of the mainsuction will stop the common drive shaft by switching off the mainelectric motor whose control circuit is actuated by a switch such asdesignated 36.

Though the present invention is very adaptable to any number ofindustrial and technical applications, it is particularly appropriatefor controlling circular knitting machines which embody or employ avacuum system to draw down the garment being knit and thus provideuniform tension which is so necessary for a successful knittingoperation.

While there has been described a preferred embodiment of a vacuumfailure stop motion device, obviously many variations and modificationsmay be made in the chamber, the switching device and the baffie as wellas other components without departing from the spirit and purpose of theinvention. Such modifications are contemplated and are considered withinthe scope of the appended claims.

I claim:

1. A vacuum failure stop motion device associated with a vacuum systemmaintaining a continuous vacuum within an evacuating tube in combinationwith a circular knitting machine, said device comprising: a chambercommunicating with the evacuating tube; activating means positionedadjacent said chamber moveable from an active to an inactive position;piston means moveable within said chamber communicating with saidactivating means, said piston means responsive to at least one change inthe vacuum magnitude to actuate said activating means.

2. A device is claimed in claim 1, said chamber having vacuum-sensedapertures opening into the tube to reflect a change in vacuum magnitudein the chamber interior.

3. A device is claimed in claim 1, said activating means including aswitch having a moveable finger responsively activating and deactivatingsaid switch upon displacement through-a predetermined distance.

4. A device is claimed in claim 1, said piston means including a batheand a piston rod connecting said baffie with said activating means.

5. A device is claimed in claim 3, said piston means including a bafiieand a piston rod connecting said baffle and said switch moveable finger.

6. A device is claimed in claim 2, said activating means including aswitch having a moveable finger responsively activating and deactivatingsaid switch upon displacement through a predetermined distance, and saidpiston means including a bafiie and a piston rod connecting said bafflewith said switch moveable finger.

7. A device is claimed in claim 1 further comprising an electric powersource and electric motor means driving the knitting machine during theknitting operation wherein said activating means energizes anddeenergizes said motor means to start and stop the knitting machineFOREIGN PATENTS in response to a change in the tube vacuum magnitude.558,876 3/1957 Italy 66 149S 1,058,783 11/1953 France 30235 ReferencesCited UNITED STATES PATENTS 5 MERVIN STEIN, Primary Examiner 2,625,0261/1953 Lawson 66-157 US. Cl. X.R.

3,455,124 7/1969 Rossler 66149S 66157

